Method to manufacture silicon quantum islands and single-electron devices

Abstract

The present invention provides a method of manufacturing a single-electron transistor device (100). The method includes forming a thinned region (110) in a silicon substrate (105), the thinned region (110) offset by a non-selected region (115). The method also includes forming at least one quantum island (145) from the thinned region (110) by subjecting the thinned region (110) to an annealing process. The non-selected region (115) is aligned with the quantum island (145) and tunnel junctions (147) are formed between the quantum island (145) and the non-selected region (115). The present invention also includes a single-electron device (200), and a method of manufacturing an integrated circuit (300) that includes a single-electron device (305).

Description

TECHNICAL FIELD OF THE INVENTION[0001]The present invention is directed, in general, to the manufacture of a semiconductor device and, more specifically, to a method of manufacturing of a silicon quantum island for a single-electron device.BACKGROUND OF THE INVENTION[0002]The continuing demand for increasing computational power and memory space is driving the miniaturization of integrated circuits. To sustain progress, miniaturization will soon be driven into the nanometer regime. Unfortunately, conventional devices cannot be scaled down straightforwardly because of problems caused by parasitic resistance, scattering and tunneling, among other things.[0003]Single-electronics offer solutions to some of the problems arising from miniaturization. Single-electronic devices can be made from readily available materials and can use as little as one electron to define a logic state. Unlike conventional devices, single-electron devices show improved characteristics when their feature size is...

AI Technical Summary

Benefits of technology

The present invention provides a method of manufacturing a single-electron transistor device by forming a thinned region in a silicon substrate and aligning it with a non-selected region to form tunnel junctions. The invention also provides a single-electron device and an integrated circuit with the single-electron device and a MOS device. The technical effects include improved performance and reliability of the single-electron device and the integrated circuit.

Problems solved by technology

Unfortunately, conventional devices cannot be scaled down straightforwardly because of problems caused by parasitic resistance, scattering and tunneling, among other things.

The practical implementation of single-electronic devices has yet to be realized, in part because there is no practical process technology to mass produce nanometer-scale single-electron device structures.

Additionally, no process exists for manufacturing single-electronic devices that can be readily combined with present procedures for manufacturing very large scale integrated circuits (VSLI).

One reason for the lack of a practical process involves problems in the manufacture of quantum islands and their alignment with other device components.

Conventional methods for forming quantum islands are either impractical or incompatible with existing VSLI process technology.

For instance, it is impractical to produce quantum islands in commercial numbers by scanning tunneling microscopy (STM) or atomic force microscopy (AFM).

It is also problematic to form quantum islands by using lithographic procedures to select an area of silicon and then performing repeated cycles of etching and oxidation to define the island.

The pitch between quantum islands formed in this manner is undesirably large (e.g., center to center distance of greater than 200 nanometers) because of the limits in resolution of existing lithographic technology.

Quantum islands formed by growing germanium, or depositing gold clusters, on silicon substrates suffer from alignment problems.

That is, once gold or germanium quantum islands are formed on the substrate, it is very difficult to reproducibly align electrical contacts with the quantum island.

This, in turn, makes it difficult to produce single-electron devices with reproducible performance characteristics, and to connect such devices to traditional device components, such as metal oxide semiconductors (MOS) devices.

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